The aims of this project are to develop and apply competing hazard models representing the age pattern of mortality throughout life, and parity survivorship after a previous birth. The mortality model to be investigated is a five-parameter model taken from the ecological literature. The parity survivorship model is based on the Erlangian distribution (a special case of the Gamma distribution). Simplex methods of fitting hazard functions to demographic data by least squares will be developed to reduce the computer time necessary to apply these models and to increase the accuracy of the fit. The accuracy and statistical stability of both models with small sample sizes will then be evaluated using simulated data. Applications to be undertaken include: 1. Determination of the range of parameter values represented in a large worldwide sample of life tables, and development of a system of model life tables based on this range of variation, 2. An investigation of the relationship between cause of death structure and the age pattern of mortality, using a worldwide sample of full and decremented life tables, 3. An analysis of the North American Hutterite population to determine the influence of infant mortality on parity intervals, and the influence of level of inbreeding on demographic rates.